Method and apparatus for forming socket-head cap-screw blanks



June 29, 1965 H L M GLELLAN ETAL 3,191,204

METHOD AND APPARATUS FOR FORMING SOCKET-HEAD CAP-SCREW BLANKS 8Sheets-Sheet 1 Filed Sept. 17, 1962 J1me 1965 H. L. M CLELLAN ETAL3,191,204

METHOD AND APPARATUS FOR FORMING SOCKET-HEAD CAP-SCREW BLANKS FiledSept. 17, 1962 8 Sheets-Sheet 2 June 29, 1965 H. M CLELLAN ET 3,191,204

METHOD AND AP SOCKET-HEAD PARAT FOR F G CAP- EW BLA Filed Sept. 17, 19628 Sheets-Sheet 3 June 29, 1965 H. M CLELLAN ETAL 3,

METHOD AND APPARATUS FOR FORMING SOCKET-HEAD CAPSCREW BLANKS Filed Sept.17, 1962 8 Sheets-Sheet 4 &

,6/ 52 F 5 A V 5 kka June 29, 1965 H. L. M CLELLAN ETAL 3,191,204

METHOD AND APPARATUS FOR FORMING SOCKET-HEAD CAP-SCREW BLANKS FiledSept. 17, 1962 8 Sheets-Sheet 5 4 rraleA/zxs June 29, 1965 H. M CLELLANETAL 3,191,204

METHOD AND APPARATUS FOR FORMING SOCKET-HEAD CAP-SCREW BLANKS 8Sheets-Sheet '7 Filed Sept. 17, 1962 I AIII INVENTORS HEFEEP? 4.#4442644444 0a,1/A0 5. #0515 BY f/cx/g/ Mm/fn/M/ June 29, 1965 H.MCCLELLA ETAL 3,191,204

METH AND APPARATUS R FORMING SO T-HEAD CAP-SCREW BLANKS Filed Sept. 17,1962 8 Sheets-Sheet 8 004/440 6. Mass 3,191,204 METHOD AND APPARATUS FORFORMENG SQCKET-HEAD CAPSCREW BLANKS Herbert L. McClellan and Donald E.Huss, Tifin, Ohio,

assignors to The National Machinery Company, Tiffin,

Ohio, a corporation of Ohio Filed Sept. 17, 1962, Ser. No. 223,962

11 Claims. (Cl. 10-44) This invention relates generally to forging, andmore particularly, to a novel and improved method and apparatus for coldforging articles having upset portions such as socket-head cap-screwsand the like.

In the manufacture of socket-head cap-screws, it has been customary toshear blanks from stock and then upset and pierce the cap-screw blank toform the socketed head and shank. The blank is then generally machinedon both the head and shank end and threaded to complete the cap-screw.The machining or facing of the head of the blank has been used to formthe chamfer at the edges, maintain head height within the requiredtolerances, remove the tapered section of the hex hole, and to providean improved finish on the head surface for appearance and for safetysince such facing removes any sharp edges. The machining of the shankend of the blank has been performed in a pointer as one of theoperations of a combined machine incorporating heading, pointing andthreadrolling but the facing operation at the head end has generallyrequired separate handling and the provision of a separate machine toperform this function. With such machining, difiiculty has sometimesoccurred since the cutting operation often leaves a burr at the hex holein the head. This separate facing operation has created ad ditionalmachine investment, expense of maintenance and operating costs as wellas providing difficulties, as an example, in the chucking of the screwswithout damaging the thread and accurate positioning of the blanks sothat the machining operation will be properly performed.

In addition, the cost of material has been increased since the facingoff or scraping on a cap-screw removes as scrap about 5 of material. Inhigh production manufacture, the accumulative cost of such scrap issubstantial.

The need of machining the head end of the blank has often been createdby the occurrence of islands on the ends of the initial blank shearedfrom wire stock which produce sharp edges and fiaws in the headed end ofthe blank. These islands which constitute small projections partiallysevered from the piece to which they are joined, leave sharp edges atthe completion of the heading operation which can snag or cut the usersfingers and which detracts from the appearance of the finished product.

In the method and apparatus incorporating this invention, an improvedshear is provided for cutting the initial blanks from the wire or rodstock without forming islands or excessive uneveness in the end orcut-off surfaces. The ends, however, of such initial blanks are notsquare. In the first forming operation, the blanks are positioned in dieassemblies and coned in a manner which concentrates the pressure on theend face of the blank to provide complete squaring of the end. The diesand tools at this step in the operation are also arranged to preventtwisting, bending or eccentric movement of the blank.

The blank is thereafter upset, forming a head having a smooth end faceand a well filled crown around the outer edges thereof. Here again, thedies and tools of upsetting are arranged so that the pressure isconcentrated on the end face so that a good finish and close toleranceresults. The inner end of the headed part does not flow into the cornersof the die cavity, leaving unfilled corners which are filled in the nextoperation.

In the final forming operation, the head is pierced with United StatesPatent 0 "ice a polygonal punch or socketing tool. During the firstportion of punch penetration, the material of the head is upset forwardinto the lower corners of the die cavity to form a sharply filled head.This forward upsetting results in a cutting in of the punch from the endface and does not produce distortion of the crown or end face. As soonas the lower corners of the head are sharply filled the pressure buildsup causing backward extrusion of the head along the punch and die,thereby completing the finished blank.

Because the cut-off is performed without creating islands on the shearedface, a high quality finish is produced without sharp cutting edges onthe end face. The shearing also accurately provides the proper volume ofmaterial so tolerances are accurately maintained without a finishing orfacing cut on the head. As a result, the finished cap-screw can beformed in a single combined machine having a progressive header, apointer for machining the shank end of the blank and a thread roller forproducing the required threads on the shank. Such a combined machine isof the general type disclosed in the United States Patent to Frost, No.2,020,658 dated November 12, 1935.

It is an important object of this invention to provide a novel andimproved method and apparatus for forming high quality socket-headcap-screw blanks without requiring a machining operation to finish thehead face of the blank.

It is another object of this invention to provide a novel and improvedmethod and apparatus for shearing blanks from cylindrical rod or wirestock having a clean welldefined out without islands or other surfacedefects.

It is still another object of this invention to provide a method andapparatus for shearing cylindrical blanks from wire or rod stock whereinthe sheared ends are free from substantial surface defects incombination with an upsetting operation to square the end of such blankto form a smooth and square end face.

it is still another object of this invention to provide a novel andimproved method and apparatus for forming socket-head cap-screws whereinmeans are provided to trap a predetermined amount of lubricating oil atthe end of the socketing tool for the lubrication thereof during thesocketing operation.

It is still another object of this invention to provide a novel andimproved method and apparatus for forming socket-head cap-screws havinga charnfer adjacent to the end of the socket and a crowned outer edge onthe socket end of the head without machining.

It is still another object of this invention to provide a novel andimproved apparatus for shearing a blank from rod or wire stock whereinthe shear is provided with spacing between the cutter knife and quill toprevent the occurrence of islands or deep surface imperfections combinedwith a squaring operation producing a smooth and square end on theblank.

It is still another object of this invention to provide a novel andimproved method and apparatus for forming socket-head cap-screw blankswherein a shallow recess is formed in the end of the blank during theheadingoperation and a socketing tool is thereafter pressed into saidrecess to form the required socket in which the recess and socketingtool are proportioned and arranged to provide for the trapping of apredetermined amount of lubricating oil for the lubrication of the endof the socketing tool.

It is still another object of this invention to provide a novel andimproved stripper for shaping the end of a blank and also stripping theblank from a tool.

It is still another object of this invention to provide a novel andimproved die mounting providing preloading at one surface greater thanthe preloading at other sur- Further objects and advantages will appearfromthe following description and drawings, wherein 7 FIGURE 1 is a planview of a progressive heading machine incorporating this invention;

FIGURE'Z is a section through the machine in front of the die breastillustrating the cutter and transfer mechanism;

FIGUREY3 is an enlarged fragmentary section showing the structuraldetails of the cutter quill and cutter ring;

FIGURE 4 is a view taken along 4-4 of FIGURE 3 illustrating the cutterring face;

FIGURE 5 is an enlarged section illustrating the operation of cuttingimmediately before the rupture separates the blank fro'm the stock;

FIGURE'6'i-s a plan view in longitudinal section dies and tools at thefirst die'station illustrating the position of the elements when thesliding sleeve on the header side engages the die in the die breastpreventing further forward movement of the sleeve;

FIGURE 7 is a view similar to FIGURE-6 illustrating j at a shearingstation' 19 into blanks 21' illustrated in FIGURE'16 and transferred tothe first die station 24. 7 Referring to FIGURE 2, the stock is engagedby a shear including a vertically reciprocable knife assembly 22 whichshears off the blank 21 and carries it upward into horizontal alignmentwiththe blank working stations wherein it is gripped by a first pair oftransfer fingers 23. A knockout .(not shown) is used to push the shearedblank 21 'from'the vertically reciprocating knife 22.

The transfer mechanism is arranged to simultaneously carry blanks fromthe shearto a first die station '24, from the die station 24 to a seconddie station 26, from the'second die station 26 to a third die station 27and from the third die station 27 to a blank receiving staof the tion23. Transfer fingers 23 are mounted on a carriage 29 which reciprocateshorizontally back and forth in front of, the die breast to accomplishthis action. The fingers 23 are operated to grip blanks ejected fromthedies and I progressively position the blank'in front of the next diestation for the subsequent operation. 1 The entire transfer system ispowered in timed relationship to the movement of the header slide sothat blanks are progressively moved the position of the elements at thecompletion of the operation at the first die station;

FIGURE 8 is a plan view in longitudinal section of the second diestation wherein the head is upset at the end of the blank illustratingthe elements .atthe completion of the operationperformed at thisstation;

FIGURE 9 is a plan view in longitudinal section of the third and finalworking station wherein the socket is formed in the head illustratingthe elements at the point in the stroke at which the forward upsettingis completed and the backward extrusion is commenced;

FIGURE 10 is a view similar to FIGURE 9 illustrating the elements at thecompletion of the Working stroke;

FIGURE 11 is an enlarged fragmentary view of the head of the blankformed in the second die station of FIGURE 8 illustrating the shape ofthe tool forming a shallow recess in the head; 7 v. I

FIGURE 12 is an enlarged fragmentary section of the socketing tool atthe moment it engages the head formed 'in the-second die stationillustrating how lubricant is trapped at the end of the socketing' tool;

FIGURE 1-3 is a side elevation in longitudinal section of the third diestation illustrating the structure of the air hammer and stripper;

FIGURE 13a is a schematic illustration of the'stripper third ting 'edge38 extending back from the face of the cutter to each of the diestations and to the blank receiving station 28. The structureillustrated for transferring the blanks progressively to each blankworking station is dis- "2,026,823 dated January 7, 1956.

Wire stock 18 is fed .through the die breast 16 at the shearing station19' by conve'ntionalfeed"rollers until it engages an adjustable stockgauge 31. When the stock 18 engages the gauge 31, the proper volume ofstock necessary to form the finished bolt'blank is sheared from thestock by vertical movement of the knife 22.

Referring to FIGURES 3 through 5, a hardened quill '32 is mounted inyabore30 in the die breast'16 and is formed with a bore 33 through whichthe stock 18 extends' A hardened cutter'ring 34 is mounted on the knife22 and is formed with a similar bore 36 aligned with the bore 33 when:the knife 22 is in the lower position illustrated inFIGU RE 2. Afterthe forward end of the stock engages the stock gauge 31, the knife 22carries the cutter ring 34 upward shearing the blank 21 from the 7 stock18.

. Where the greatestthickness of material must be sheared.

In order to. prevent the formation of islands in the cut end of theblanks 21 or otherdrastic surface irregularities, the end of the quill32 is formed with curved cutting edge 37 e xtending back from the endface of the quill 32. v

Similarly, the cutterring 34 is formed with a curved cutring 34. Withthis structure, the cutting edges 37 and 38 are spaced apart thegreatest distance in the zone Since the'stock is cylindrical, thethickness sheared is FIGURE 18 is a side and end view or the blankformed quill 32 and cutter ring 34 respectively, their faces are in thesecond die station; and

FIGURE 19 is a side and endyiew of the final blank formed in the thirddie station. 7

Referring to FIGURE 1, the numeral 10 designates greatest along a planethrough the axis of the stock paral- -lel to the direction of shearingmovement of the cutter ring 34. The depth of the zone to be'sheareddecreases at points laterally spac'ed from this plane.

To form the curved cutting edges 37 and 38 on the cutter ring. Thisrecess 40 in the cutter ring 34 is best a bed frame of any suitabledesign. "A main crankshaft 11 is journaled'on the opposite sides of thebed frame and is providedwith a crank 12 having a c nnecting rod 13journaled thereon. A countershaft 14 is geared to the crankshaft 11 forrotation at the same speed as the crankshaft. The bed frame is providedat its forward end; with a die breast 16 and within a slideway formed inthe frame a header slide 17 is mounted to reciprocate toward and awayfrom the die breast 16." The connecting rod 13' is pivoted on the slide:to producewthe reciprocation thereof in response to crankshaftrotation.

Wire or rod stock 18 is fed 'throughthe bed frame 10 by conventionaltype feed rollersor the like and is sheared il-lustratedintFIGURE ,4.The curved cutting edges are formed by the intersection of the bores33and 36 and curved recess 40 and have a projected shape on a planethrough the axis of the bores 33 and 36 and perpendicular to thedirection of cutter ring movement as illustrated in FIGURE 31. I Y Y Thequill 32and;cutter ring 34 are mounted so that their respective recesses40 extend parallel to theline of cutter ring movement. The quill 32 isadjustable axially in the bore 30 to provide adjustment of the runningclearance to about .00 between the face of the cutter and the faceof thequill. Any suitable means, such as a set screw 30a, may be used to lockthe quill in its adjusted v position. The spacing between the cuttingedges 37 and 38 is determined by the ductility of the stock. Stock whichhas greater ductility requires a greater spacing between the cuttingedges 37 and 38 which is achieved by grinding of both the cutter andquill.

. Referring to FIGURE 5, as the cutter ring 34 moves upwardly relativeto the quill 32, the upper portion 37a of the cutting edge 37 (indicatedby a dotted line) cuts into the upper part of the stock 18. Similarlythe lower portion 38a of the cutting edge 38 cuts into the lower :sideof the stock 18. This cutting or shearing of opposite sides of the stock18 continues until the condition illustrated in FIGURE 5 is reached. Atthis point in the shearing operation, the unsheared section rupturesalong the dotted line 45 connecting the portions 37a and 330. This lineor plane of rupture is inclined relative to the direction of shearingforce and tends to approximate the natural plane of rupture determinedby the material properties of the stock 18.

The-axial spacing between the cutting edges is developed by grinding thequill and cutting ring until the angle of the plane of rupture 45approaches the natural angle of rupture of the material. When thiscondition is reached the material of the stock ruptures cleanly along asingle plane .and islands or excessive surface imperfections areeliminated. This also results in greater uniformity of blank volume.

The curved forms of the cutting edges 37 and 38 results in axiallyprojecting portions 37b and 38b respectively, at the sides of therecesses 40. These projections form a curved profile in the shearedportion of the out which generally follows the inclined rupture plane toinsure that the rupture surface will be clean across the entire end ofthe blank. The forward ends of the projecting portions 37b and 38b arehowever, axially spaced from each other so that clearance is provided toprevent wiping damage to the rupture surface as the cutter ring 34continues to move to its upper position.

The blank 21 is carried by the transfer fingers 23 from the shearingstation 19 to the first die station 24 illustrated in FIGURES 6 and 7.Mounted in the die breast 16 at the first die station 24 is a die holder46 which in turn supports an extrusion die 47. The extrusion die 47 isformed with an entry portion 48, having a diameter substantially equalto the diameter of the blank 21, leading to an extrusion throat 49 witha diameter equal to the required shank diameter of the bolt. A knockoutpin 51 is positioned with its end 52 engageable .with the inner end ofthe blank when the proper amount of blank material is extruded throughthe extrusion throat 49. Engagement of the end of the blank with the endface 52 of the knockout pin 51 prevents further inward movement of theblank through the extrusion throat 49 and also operates toprovide somesquaring of the end face of the blank.

Mounted on the header slide .17 is a sliding sleeve die 53 supported foraxial movement relative to the header slide 1 7 Within a bearing sleeve54. A key 56 mounted in the header slide 17 extends into an elongatedkeyway 57 and operates to limit axial movement of the sliding die 53relative to the header slide 1-7 in a direction toward the die breast1-6. A spring 58 extends between a backup plate 59 and a shoulder 61 tobias the die sleeve 53 toward the forward extreme position of its travelrelative to the header slide .17 as illustrated in FIGURE 6. The slidingdie 53 is formed with a conical coning section 62 extending back to acoaxial bore 63. An upsetting tool 64 extends into the bore 63 with aclose fit for lateral support and is formed with an enlarge-d head 66engageable with a shoulder 67 in the sliding die 53 to limit forwardmove ment of the upsetting tool 64 relative to the sliding die 53. Abackup pin 68 extends between the rearward end of the upsetting tool 64and the backup plate 59 to limit rearward movement of the tool 64 andtransmit the upsetting loads to the header slide 1-7.

g The upsetting tool 64 is formed with a flat end face 69 engageablewith the end of the blank 21 positioned at the die station 24 as theheader slide 17 moves toward the die breast 16. The bore 63 in thesliding die 53 has a diameter substantially equal to the diameter of theblank 21 so that it provides substantial lateral support for the outerend of the blank preventing bending of the blank or the like during theextrusion of the inner end through the extrusion throat 49. As discussedabove, the ends of the blank 21 are formed with a clean-cut which,however, is not square. Therefore, initially the engagement between theend face 69 and the end of the blank 21 is eccentric and would producebending of the blank if it were not for the lateral support of the bore63 of the sliding die 53.

As the header slide 17 moves toward the die breast 16, the sliding die53 is maintained in its forwardmost position by the spring 58.Therefore, the blank is well supported at it is pushed through theextrusion throat 49 until its inner end engages the end face 52 of theknockout pin 51.

FIGURE 6 illustrates the position of the various elements at the pointin the stroke when the forward end of the sliding die 53 engages theface of the die 46 preventing further forward movement of the slidingdie 53. The sliding die is formed so that the coning section 62 isspaced from the end of the extrusion die 47. The continued movement ofthe header slide :17 toward the forward dead center position illustratedin FIGURE 7 continues to carry the upsetting tool 64 forward causing theblank to move along the sliding die 53 and extrusion die 47 until theinner end engages the end face 52 of the knockout tool 51. Suchengagement prevents further forward movement of the blank and initiatesthe upset in the coning section 62 of the sliding die 53.

The upsetting of the end of the blank occurs while the sliding die 53 isstationary with respect to the die breast 16 so the upsetting requiresmovement of the end of the blank relative to the coning section 62 ofthe sliding die. Friction between the walls of the section 62 and thebore 63 resists such forward movement and results in a high pressurebetween the end of the blank and the end face 69 of the upsetting tool64. This produces a pressure concentration which assures that the endface 72 of the blank 73 formed in the first die station 24 is ironed outand is smooth and square as illustrated in FIG- URE 17. The radialconfinement of the stock in the sliding die 53 produces a well-filledcone blank wherein the blank 73 is symmetrical about its central axis.

As the header slide 17 moves back from the die breast 16, the knockoutpin 51 is pushed forward by a knockout drive 74 illustrated in FIGURE 1to eject the blank 73 from the die 47. Transfer fingers 23 grip theblank 73 as it clears the die 47 and carry the blank into a position inalignment with the second die station 26 illustrated in FIGURE 8.

Mounted in the die breast 16 at the second die station 26 is a dieholder 76 formed with a converging tapered shoulder 77 engaging andsupporting a die insert 78 having an external taper matching the taperof the shoulder 77. Positioned behind the die insert 78 is a second dieinsert 79 which is laterally supported in a bore 81 formed in the dieholder 76. Rearwa-rdly of the second die insert '79 is a tubular thrustmember 32 pressed against the rearward end of the second die end insert79 by a mounting ring 83. The mounting ring 83 is threaded into theinner end of the die holder 76 and is formed with an end face 84 hearingagainst a shoulder 86 on the thrust member 82. The rear-ward end of themounting ring '83 engages a backup plate 87 which, in turn, transmitsthe upsetting forces to the frame of the machine.

The first die insert 78 is formed with a central bore 88 whichcooperates with an end face 89 on the second die insert 79 to define ahead cavity in which the head of the blank is upset. Extendingrearwardly from the end face 89 the second die insert 79 is formed witha through bore 91 coaxial with the bore 83 and also aligned with a bore92 extending through the thrust member 82. The

, awash 7 v bores 91 and 92 have a diameter substantially equal to thediameter of the extruded portion of the blank 73 so .that the blank 73slides easily intothe dies prior to'the upset. A knockout pin 93 extendsinto the bore 92 and is positioned With its end face 94 engageable withthe inner Mounted on the header slide 17 at the second die if station 26is a tool holder 96 which supports an upsetting tool ring 97 inalignment with the first die insert 7 8. Positioned behind the tool ring97 is a backup plate 98 which transmits the upsetting loads to the toolholder 96. The tool holder 96 in turn transmits the upsetting loadsthrough a second backup plate 99 to the header,

slide 17. The tool ring 97 is formed with a central bore 101 having adiameter slightly larger than the distance across the corners of the.sock-etxul-timately formed in the blank. Positioned within the boreltllis an indenting pin 102 formed with an endface 103 in the shape of atruncated cone with an angle of about 80' to the axis of the 135 toprevent theent-raprnent of air or lubricating oil. The Venting at thelower corner results in .a sharp corner atthe bottom" of the head and afiat surface on the under side or bearing surface of the screw head. Thehigher preload adjacent to the. face of the die results in a constantdiameter on the head from top to bottom. a I

Positioned behind the first die insert 126 is a second die element 127laterally supported in abore 128 in the die holder 121. Inward from thesecond die element 127. is a tubular thrust member 129 which is clampedin position by a mounting ring 131, threaded into the die holder 121.The forward end ofthe thrust member 129 engages the rearward end of thesecond die element 127 clamping it in position againstthe inner face ofthe first die element 126 and in turn holds the'first die element 126against the conical inner face 123. The end of the mounting a ring 131seats against a shoulder 132 in the thrust mempin and symmetricallyarranged air vents 100 on its outthe socket formed in the nextoperation.

The tool ring 97" is formed with a recess 107 having a rounded corner at108. The roundedcorner 198 forms the required crown edge on theupper endof the finished head.

the blank 73 positioned at the second die station 26 is engaged bythe.indenting pin 102 and pushed into the dies until its innerend engagesthe end face 94 of the knock-v out tool 93. This prevents further inwardmovement of the. blank. Continued movement of the headerslide toward thedie breast causes the end of the blank to be upset .to the conditionillustrated in FIGURE 8 wherein the initial headed blank 109 illustratedin FIGURE; 18 e is formed. The blank 109has a straight shank 111 and Asthe header slide 17 moves toward the die breast '16,

her 129 and the rearward end of the mountingring is seated againstthebackup plate 87. Therefore, the form- .ing loadsare'transmittedthrough the thrust member 129 and the mounting ring 131to the backup plate 87.

In the. illustrated embodiment, the blank is of the type 'whichisthreaded for only a portion of the shank length.

Therefore, an extrusion die 133 is mounted at'the forward end of thethrust member 129 and is formed with an extrusion. throat 134 whichreduces the diameter'of the shank in the area to be threaded so that thethread rolled on the shank will have a maximum diameter equal to thediameter of the unthreaded portion of the shank. The end face 136 of thesecond die insert 127 cooperates with a bore 137 to define a die cavityin which the head is formed. The second dieelement 127 is formed with athrough bore 138 coaxial with the bore 137 and also coaxial withtheextrusion throat 134. The tubular thrust member 129 has a bore 139coaxial with the extrusion throat. 134 and formed with a diameterslightly larger a head portion 112. As the headporti-on .112 is upsetinto engagement with the wall of the bore 88, afriction resisting inwardmovement of the blank material is de veloped which again producesincreased pressure on the upper face resisting further :upsetting.Therefore,--the upper face of the blank is smoothly polished andarounded corner at 113 is formed. Also, the indenting tool 102 forms theshallow recess 114. The corner 116 is not sharply filled since higherpressures are required to flow material into sharp corners particularlywhen the resistance 7 due to frictional engagement with the cavity wallresists such flow. V Y e V e As the header slide 17 moves back from thedie face,

the knockout pin 93 is pushed forward by the knockout drii e 74 to ejectthe blank 199 from the dies. Transfer fingers 23. grasp theblank 109and-move it to the third 'inner face .123. This difference in angleprovides more press at the face of the first die insert 126 and moreforcie bly-restrains the insert againstexpansion attheface; The lowercorners of the die cavity are also vented by grooves than thediameter,of the extrusion throat. A knockout pin 141 is. positionedwith itsforward end142 in the bore 139 and engageable with the end of the shankof the blank when the proper amount of extrusion through the extrusionthroat 134 is completed.

'A .tool holder 143 is mounted in the header slide 17 at the third diestation 27 and .is formed with a central bore 144'which laterallysupports a punch holder 146. Mounted within'the punch holder '146 is apiercing or socketing tool 147 formed with an enlarged rearward end 148engageable witha shoulder. 149 in the punch holder 146 to'prevenfforward .movement of the piercing tool relative to the punch.holder 146. The hearward end of the enlarged'end 148 seats against abackup pm 151 which is in turn seated against a thrust member 152'mounted in the header slide 17. 'A wedge 150 adjustably locates thethrust member 15 2. The forward end of the piercing tool .147 is formedwith a hexagonal end portion .153 with a conical truncated cone 154 atits forward face.

Because thelower corners 116 of the" blank 109 are unfilled, the'first,action which occurs at the third die station 27 as the piercingtool 147enters the, headis forward upsetting causing the metal of the head toflow into the corners sharply filling the lower corners of the head. Asa result, the piercing tool 147 cuts into the head past the roundedcorners 113 and does not change the contour of the upper face of thehead. FIGURE 9 illustrates the "positions of the elements at the end ofthis forward upsettingv phase. q 1 7 As soon as the lower corners aresharply filled, continued movement of the piercing tool 147 into thehead,

causes backward extrusion along the hex portion 153, thus increasing theheightof the finished head to that shown in FIGURE 10; Since the initialportion of the piercing operation does not produce lateral forces, thechamfer around the hexagonalsocket' at the upper face of the socket, thediameter of the indenting tool 102 may be reduced to a diameter nogreater than the diameter across the flats of the hexagonal portion 153of the piercing tool 147.

Referring to FIGURES 11 and 12, the angle of the truncated cone of thepiercing tool 147 is less than the angle of the cone 103 of theindenting pin 102 so that lubricating oil will not be trapped by thepiercing tool adjacent its outer edges. However, the flat end face 156illustrated best in FIGURE 12 has a diameter greater than thecorresponding flat end face of the indenting pin 102 so that a smallcontrolled size pocket 155 is provided to entrap lubricating oil as thepiercing tool enters the head. This entrapped lubricating oil serves tolubricate the end of the piercing tool during the piercing operation andthereby increasing the tool life. It is important to insure that thecorrect amount of luibricant is entrapped since insuificient amounts oflubricant produces excessive punch wear and excessive lubricant causesradial lines at the inner end of the socket which are ragged, detractingfrom the appearance of the finished article and producing stressconcentrators. The pump and nozzle for delivering the lubricant to thetool and dies has not been shown since they are well known in the art.

As the header slide 17 moves back after the completion of the workstroke at the die station 27, the knockout punch 141 is pushed forwardby the knockout drive 74 to eject the finished blank from the dies atthe third die station 27.

A stripper mechanism illustrated in FIGURES 9, 10, 13 and 14 is providedto perform the combined functions of stamping, lettering or numbering onthe upper surface of the head of the cap-screw blank around the socketand also strip the blank from the socketing tool 147 as the header slide17 moves back from the die breast 16. The stripping mechanism includes astripper ring carrier 161 supporting a stripper ring 162. The carrier161 is slidably supported by push pins 163 guided in bearings 164mounted in the tool holder 143. The push pins 163 are anchored in thecarrier 161 against a shoulder 166 by mounting bolts 167 threaded intothe ends of the push pins 163. The views of FIGURES 9 and onlyillustrate one push pin 163 and mounting bolt 167 since these views weretaken along a broken plane section arranged to also illustrate thespring mechanism for resiliently urging the stripping mechanism towardthe rearward position. However, two symmetrically arranged push pins 163and mounting bolts are provided on opposite sides of the carrier asillustrated in FIGURE 14.

To urge the. carrier 62 toward the rearward position illustrated, springbolts 168 symmetrically arranged as illustrated in FIGURE 14, projectthrough the carrier 161 into axially extending bores 169 formed in thetool holder 143. Nuts 171 are threaded onto the ends of the bolts 168.Springs 172 extend between the nuts and face plate 173 mounted on theforward face of the tool holder 143 by bolts 174 and operate toresiliently bias the carrier 161 and stripper ring 162 toward therearward position illustrated.

The stripper ring 162 is moved forward relative to the header slide 17into engagement with the upper face of the blank 117 at two separatetimes in the cycle and performs two separate functions. The firstfunction is to stamp any desired marking on the upper face of the blankhead around the socket and the second is to strip the blank from thesocketing tool 147. Referring to FIG- URE 14, the stripper ring 162 isformed with raised lettering which stamps the desired figures orlettering on the head of the blank.

In FIGURE 13, the mechanism for moving the stripper ring 162 forward isillustrated. The rearward ends of the push pins 163 engage the forkedupper end of a stripper lever 175 pivoted at 176 on the header slide 17.The rearward side of the lever 175 seats against an anvil 177 slidablymounted in a hollow cylinder 178 mounted in a bore 179 in the headerslide 17. The anvil 177 is formed with a flange .181 engageable with theforward end of the cylinder 17 8 to limit rearward movement of the anvil177. Slidably located in the cylinder 178 is an impact piston 182closely fitting the inner wall of the cylinder, a spring 183 extendsbetween the piston 182 and anvil 177 normally maintaining the piston inthe rearward position illustrated in FIGURE 13. A spring guide 184 ismounted on the anvil 177 to prevent buckling of the spring 18 3.

Air under pressure is supplied through any suitable valve (not shown) toinlet passage 186 formed in the header slide 17 to the rearward end ofthe bore 179. The cylinder 178 is formed with an annular recess 187communioating between the passage 1 86 and radial ports 188 extendingthrough the cylinder walls. Seals 1 89 on the cylinder 17 8 engage theinner wall of the bore 179 to prevent leakage therealong. When air underpressure is admitted through the passage 186 to the rearward end of thepiston 182, the piston travels forward along the cylinder 178 until itimpacts the anvil 177. A considerable amount of free travel is providedso that the piston 182 has a substantial velocity when it engages theanvil. Engagement of the piston 182 with the anvil 177 causes the anvilto move forward, and through the stripper lever and push pins 16-3,drive the stripper ring 162 against the upper face of the blank 117located in the dies. Since the kinetic energy of movement of the piston182 must be absorbed in a very small stroke when the stripper ring 162engages the blank head, suflicient forces are developed to stamp therequired letters or numbers into the upper surface of the head. Thevalve controlling the air under pressure to the passage 186 is timed sothat the stripper ring 162 impacts against the blank while the headerslide 17 is in .the forward dead center position.

To strip the blank v117 from the socketing tool 147 as the slide 17moves back from the die breast 16, the stripper lever is rotated in acounterclockwise direction to push the pins 163 and in turn, .thestripper ring 162 forward relative to the tool 147. This prevents theblank from being carried out of the dies by the tool. In FIGURE 13a adrive for the stripper lever is schematically illustrated. A link 191 ispivotally connected between the connecting rod 13 and an arm 192 on acam shaft 193 journaled on the header slide .17. Therefore, the camshaft 193 oscillates back and forth as the connecting rod 13 swingsabout its pivot on the header slide 17 in timed relationship to thereciprocating movement of the header slide. A cam 194 on the camshaft.193 engages the stripper lever 175 to produce the requiredcounterclockwise movement thereof.

As the header slide 17 moves clear of the dies, the knockout pin 141 ispushed forward by the drive mechanism 74 to eject the finished blank atthe die station 27, into the transfer fingers 23 which carry thefinished blank to a position in alignment with the blank receivingstation 28.

Located at the blank receiving station 28 is a tubular element 196mounted in a holder 197 which is in turn, mounted in the header slide17. The tubular member 196 is sized to receive the finished blanks 1117and is mounted in alignment with a tube 198 leading out of the header.In order to prevent the blanks from dropping out of the tubular member196 as the header slide retracts, a spring loaded friction member 199 ismounted in the side of the tubular member 196 and pressed toward theblank by a leaf spring 201. Mounted in the die breast at the blankreceiving station 28 is a pusher element 202 spring biased toward itsforward extreme position by a coil spring 203. As the header slide movestoward the pusher member 262, the blanks enter the tubular member 196and are pressed therealong by the pusher member 202. The spring 203 isused to cushion the impact since there is a relatively long column ofblanks contained in the tube 198.

A method and apparatus for forming socket-head capscrew blanksincorporating this invention provides an improved shearing mechanismwhich eliminates islands in e la a the cut ends of the initial blank.The diesand tools cooperate with the shearing mechanism to form afinished blank having a head requiring no machining fthereon therebyminimizing scrap, inventory costs and machine expense. V

I Although a preferred embodiment of this invention is illustrated, itis to be understood that various modifications and rearrangements ofparts may be resorted to without thereof. in a directionperpendicular'to the axis of said stock, said shear forces being appliedat curved zones spacedaxially along said stock, the minimum axialspacing of said zones being located at'the'lateral extremities thereofwith'respect to said direction and being directly relatedtothe-ductility of the stock, the: axial spacing at portions other thansaid lateral extremities-being a departing from the scope of theinvention as defined in'the which said bores are non-aligned, a curvedcutting edge on each member at the end of its bore adjacent to the otherof said members, the projection of each cutting edge on a directfunction of the ductility of said stock and the thick-- ness ofsaid-stock in the direction of said shear forces whereby a plane ofrupture between said zones is inclined relative to the axis of saidstock, said stock being supported against substantial bending on bothsides of said plane of rupture. s

i 6. A method of forming blanks comprising shearing a piece of stockfrom cylindrical metal stock by applying opposed shear forces toopposite sides thereof in a direction perpendicular to the axis of saidstock, said shear forces beingiapplied at curved zones spaced axiallyalong planethrough the axis of said bores and perpendicular to f thedirection of movement from said first position to said second positionbeing curved, said projections being similar and opposed with thegreatest spacing at the axis of said-bores and-curving toward each otherat their extremities, said cutting edges being developtd to space saidprojections'apart a distance which is a direct function of the ductilityof said stock, and means flowing the material of said blank adjacent toits end until such material is symmetrical about the central axis ofsuch blank. 7

2. A cutter for shearing cylindrical stock having a degree of ductilitycomprising a quill member, a cutter ring member, said members each beingformed with a bore adapted to. receiveiand closely fit said stock,mounting means for moving said members from a first-position in whichsaid bores are aligned to a second position in' which said bores areparallel and non-aligned, a curved cutting edge on each member at theend ofits bore adjacent to the other of said members, the projection ofeach cutting edge on a plane through the axis of said bores andperpendicular to the direction of'rnovement from said first position tosaid second position being curved, said projections being similar andopposed withthe greatest spacing at the axis of said bores and a spacingless than said greatest spacing at their extremities,-said cutting edgesbeing developed to space said projections apart a distance which is adirect function of the ductility of said stock,

asv

' atblank from cylindrical stock by applying opposed shear said stock adistance which is a direct function of the ductility ofsaid stock andthe thicknessof the stock in a direction of said shear forceswhereby aplaneof rupture between said zones is inclined relative to the axis ofsaid stock, and thereafter laterally supporting said piece of stock indies engaging the'sides thereof to resist movement of said piece ofstock axially relative to said .dies,

' and pressing a tool against one end of said piece of stock moving saidpiece of stock along said dies With suificient pressure exerted betweensaid tool and said one end to square the piece of stock at said one end.I

7. 'A' method of forming blanks comprising shearing forces to oppositesides thereof in a direction perpendicular to the axis of said stock,said shear forces being applied at curved zones spaced axially alongsaid stock said mounting means maintaining a space between said sectingthe associated .bore and extending across said memberin a directionparallel to the direction of'movementbetween said first and secondpositionjthe intersection of said recesses and associated bores definingopposed curved cutting edges axially spaced apart, said drive meansmaintaining'an axial spacing between said quill member and cutter ring.e e

4. A method of shearing cylindrical metal stock comprising applyingopposed shear forces to opposite sides thereof in a directionperpendicular to the axis of said stoclgsaid shear forces being appliedat curved zones spaced axially along said stock a distance Which is adirect function of the ductility of said stock and the thickness of thestock in the direction of said shear forces whereby a distance which isa direct function of the ductility of "said stock and the thickness ofthe stockvin the direction of said shear forces whereby a plane 'ofrupture between said zones: is inclined relative to the axis of saidstock,

thereafter laterally supporting said blankrand dies engaging'the sidesthereof adjacent one end to resist movement of said blank axiallyrelative to said dies, and pressing a tool against said one end ofvsaidblank moving said blank along said dies with sufficient pressure exertedbetween said tool and said one end to upset said blank a point spacedfrom said one end and square said blank at said. one end, and thereafterupsetting said blank in another die forming a head thereon at said oneend.

8. A method of forming blanks comprising shearing a blank fromcylindrical metal stock byapplying opposed shear forces to oppositesides thereof in a direction perpendicularto the axis of said-stock,said shear forces I being applied at curved zones spaced axially alongsaid a plane of rupture between said zones is inclined relative t stocka distance which is a direct function of the ductility of said-stock andthe thickness of the stock in the direction of said shear forces wherebya plane of rupture between said zones is inclined relative to the axisof said stock, and thereafter positioning vone end of said blank in asleeve engaging the side of said blank adjacent said-one end andpressing the end of a tool against said one end within said sleevewhile-holding said sleeve against movementwith' said tool and excitingsufiicient pressure between said tool at one end to form said one end tothe shape of the end of said tool.

9. In a machine of the character described, a frame, a slidereciprocable relative to said frame, cutting means including a quill onsaid frame formed with a bore through which a cylindrical stock is fedand a cutting edge atthe end of said bore, a cutter element reciprocablelaterally relative to said quill, said cutter element being formed witha bore adapted to receive said stock and a cutting edge at the endthereof adjacent to said quill, said'cutting edges on said quill andcutter element being formed by the intersection of the respective boresand a concave recess intersecting the associated bore and extendingacross said cutter element and quill in a direction parallel to thedirection of movement of said cutter element relative to said quillwhereby said cutter element severs blanks from said stock having endsinclined relative to the axis of said stock, a die station on said frameand slide receiving blanks from said cutting means, a fixed die on saidframe at said die station receiving one end of said blank, a sliding dieon said slide at said die station receiving the other end of said blank,a tool on said slide having an end movable along said sliding die, andmeans holding said sliding die stationary relative to said fixed diewhile said tool moves toward said fixed die pressing said other endalong said sliding die and upsetting said blank between said dies, thefriction between said other end of said blank and said sliding dieresisting movement of said other end with said tool thereby producing amaximum pressure between the end of said tool and said other end of saidblank. 10. A method of forming socket head cap screw blanks fromcylindrical metal stock comprising applying opposed shear forces toopposite sides of said stock in a direction perpendicular to the axis ofsaid stock, said shear forces being applied at curved zones spacedaxially along said stock a distance which is a direct function of theductility of said stock and the thickness of the stock in the directionof said shear forces whereby a plane of rupture between said zones isinclined relative to the axis of said stock, thereafter positioning saidblank in a first die assembly engaging the side walls of said blankadjacent to one end thereof, upsetting said blank by pressing a toolagainst said one end and moving such tool relative to said die assembly,thereafter positioning said blank in a second die assembly with acylindrical head cavity of uniform radius adjacent said one end andupsetting said one end into said head cavity with a tool shaped to forma crowned end face at said one end and unfilled corners at the inner endof said cavity, thereafter positioning said blank in a third dieassembly having a cylindrical head cavity around said headed part ofsaid blank and pressing a polygonal punch into said end face forming apolygonal socket therein, said punch forward upsetting the headed partinto the inner corners of said third die assembly head cavity as theforward end of said punch moves past said crown and thereafter backwardextruding said headed part along said punch in the associated diecavity.

11. A method of forming socket head cap screw blanks from cylindricalstock comprising applying opposed shear forces to opposite sides thereofin a direction perpendicular to the axis of said stock, said shearforces being applied at curved zones spaced axially along said stock adistance which is a direct function of the ductility of said stock andthe thickness of the stock in the direction of said shear forces wherebya plane of rupture between said zones is inclined relative to the axisof said stock, thereafter positioning the blank severed from said stockin a first die assembly engaging the side walls of said blank adjacentone end thereof, upsetting said blank and squaring said one end bypressing a tool against said one end and moving such tool relative tosaid die assembly whereby the engagement between said blank adjacentsaid one end and said die assembly resists movement of said end withsaid tool and concentrates pressure at said one end, thereafterpositioning said blank in a second die assembly with a cylindrical headcavity of uniform radius adjacent said one end and upsetting said oneend into said die cavity with a tool shaped to form a crown and aconical recess in the end face of said one end and unfilled corners atthe inner end of said cavity, thereafter positioning said blank in athird die assembly having a cylindrical head cavity of uniform radiusaround the headed part of said blank and pressing a polygonal punch intosaid end face forming a polygonal socket therein, said punch forwardupsetting the headed part into the inner corners of said third dieassembly head cavity as the forward end of said punch moves past saidcrown and thereafter backward extruding said headed part along saidpunch in the associated die cavity.

References Cited by the Examiner UNITED STATES PATENTS 717,706 1/03McCool 83-198 1,685,377 9/28 Province et a1. 10-25 1,826,016 10/31Naylor et a1. 83-198 1,978,371 10/34 Purtell.

2,057,928 10/36 Stahl 83-51 2,227,810 1/41 Mitchell 10-24 2,559,140 7/51Wilcox.

2,621,344 12/52 Friedman 10-11 2,680,860 6/54 Friedman 10-11 2,705,3334/55 Friedman 1011 2,715,232 8/55 Egan 10--11 2,843,862 7/58 Smith 10-24ANDREW R. JUHASZ, Primary Examiner,

3. A CUTTER FOR SHEARING CYLINDRICAL METAL STOCK HAVING A DEGREE OFDUCTILITY COMPRISING A QUILL MEMBER, A CUTTER RING MEMBER, EACH MEMBERBEING FORMED WITH A BORE BEING ADAPTED TO RECEIVE SAID STOCK, DRIVEMEANS SUPPORTING SAID MEMBERS FOR MOVEMENT FROM THE FIRST POSITION INWHICH SAID BORES ARE ALIGNED TO A SECOND POSITION IN WHICH SAID BORESARE NON-ALIGNED, THE ADJACENT ENDS OF EACH MEMBER BEING FORMED WITH ACONCAVE RECESS INTERSECTING THE ASSOCIATED BORE AND EXTENDIN ACROSS SAIDMEMBER IN A DIRECTION PARALLEL TO THE DIRECTION OF MOVEMENT BETWEEN SAIDFIRST AND SECOND POSITION, THE INTERSECTION OF SAID RECESSES ANDASSOCIATED BORES DEFINING OPPOSED CURVED CUTTING EDGES AXIALLY SPACEDAPART, SAID DRIVE MEANS MAINTAINING AN AXIAL SPACING BETWEEN SAID QUILLMEMBER AND CUTTER RING.